The present invention relates to a tool for wire fencing. Specifically, the invention concerns apparatus for tightening a span of wire by taking up the slack in the wire.
A large number of devices are known in the prior art for increasing the tension in a wire, rope or similar article. For example, U.S. Pat. No. 1,476,026 issued Dec. 4, 1923 to Barber, shows a device in which a clothesline is engaged between the legs of a U-shaped cleat that extends sideways from an elongated member. When the elongated member is rotated about an axis parallel to the legs of the U-shaped member and midway between them, the clothesline or cable is wound around the legs thereby taking up the slack in the cable and increasing the tension in the cable. At the other end of the elongated member, Barber's device includes a crook that is set over the cable to prevent the handle from rotating and thereby unwinding the cable.
Comparable devices are also shown in U.S. Pat. No. 5,012,559, issued May 7, 1911 to Flannery and in U.S. Pat. No. 5,383,256, issued Jan. 24, 1995 to Wachi et al. The devices of these patents must remain engaged in the lines so long as the increased tension is to be maintained.
If a person wants to increase the tension in a number of spans of wire, such as in a wire fence enclosing a large pasture, it is necessary with the devices of the prior art to use a number of such devices. This is relatively expensive. In addition, because the handle of the device remains in the fence, it would be easy for vandals to disengage the devices of the prior art and steal them.
Inventions consisting of wire tightening devices and tools for their use are also known in the prior art. U.S. Pat. No. 912,960 issued Feb. 16, 1909 to Hestness discloses a wire stretching member and an operating member for its use. U.S. Pat. No. 5,170,536 issued Dec. 15, 1992 to McBroom discloses a tool for tensioning a wire fence around a barb-like article that remains in the fence once the tool has been removed. There are significant limitations in the use of the class of inventions represented by the above mentioned apparatuses. The Hestness' device engages the wire at two points, a looping element and a single stabilizing element. This structure makes the Hestness' invention unstable and prone to disengage from a fence when left on the wire for a significant period of time. The McBroom device is unable to alter the amount of tension at the engagement point on the fence and necessarily introduces a barb into the wire as a means of tightening the fence.